This invention relates to glasses, more particularly glasses which will transmit infrared radiation and possessing a high (&gt;500.degree. C.) glass transition temperature.
Commercially used glasses for infrared transmission capability are known to have low glass transition temperatures. Most of the known infrared transmission glasses are chalcogenide-based glasses due to their established infrared transparency and their inherent ease of fabrication. However, glass transition temperatures of these are so low as to make them uncompetitive with polycrystalline materials. For example, there are no known chalcogenide glasses which have glass transition temperatures (T.sub.g) higher than 500.degree. C.
Having high glass transition temperatures is desirable for a glass because it means increased use flexibility for the glass, generally improved durability and potential for a much more widely acceptable high performance infrared transmitting glass.
Accordingly, the primary objective of the present invention is to prepare a higher melting, higher T.sub.g, and longer wavelength (&gt;10 micrometer) infrared transmitting chalcogenide glass.